Before planting it is a good idea to find your USDA Zone info to figure out your garden schedule. The most important data that the zone info tells us is average last frost and the lowest expected temperature for your area.

You should be able to determine when you can plant alternanthera by reviewing the USDA zone info for San Jose.

Planting Calendar for Alternanthera

Frost tolerance for alternanthera:	Not tolerant of frost.
When to plant:	After the last frost.

It's a bad idea to plant alternanthera until after all chance of frost has passed because they do not do well in cold weather.

The earliest that you can plant alternanthera in San Jose is March. However, you really should wait until April if you don't want to take any chances.

The last month that you can plant alternanthera and expect a good harvest is probably September. You probably don't want to wait any later than that or else your alternanthera may not have a chance to fully mature. You can get started a couple of weeks earlier by starting your alternanthera indoors.

Last Frost Date

On average the last frost is on February 15 in San Jose. You should expect an average low temperature of 25°F in the coldest months of winter.

Since the USDA zone info for San Jose is not always accurate the actual date of last frost can change quite a bit from year to year. Half of the time in San Jose last frost occurs after February 15 so make sure that you are ready to protect your alternanthera if you have a late frost.

USDA Zone Info for San Jose

Here is the info for USDA Zone 9b.

Average Date of Last Frost (spring)	February 15
Average Date of First Frost (fall)	December 15
Lowest Expected Low	25°F
Highest Expected Low	30°F

This means that on a really cold year, the coldest it will get is 25°F. On most years you should be prepared to experience lows near 30°F.

Plants to Grow in San Jose

You may be interested in your other planting guides for San Jose.